The invention relates to a mining machine that is utilizable for the formation and/or enlarging of generally horizontal bores in coal seams, or the like. The invention has some of the same features, and functionality, as the machines in prior U.S. Pat. Nos. 4,082,362 and 4,120,535, the disclosures of which are hereby incorporated by reference herein. The device according to the present invention is particularly useful for mining coal seams having a relatively small, but varying, thickness.
The mining machine according to the present invention is for forming, and for use in, elongated generally horizontal bores in coal seams and the like. The machine includes a non-rotatable body member, with stabilizing means for insuring non-rotative movement of the body member in a bore. The body member preferably includes a pair of side wall supports extending in a first, generally horizontal, direction, parallel to the direction of elongation of the bore in the coal seam.
A single cutting head is mounted in front of the nonrotatable body member, and rotatable about a first axis. Power means are provided for rotating the cutting head about the first axis to effect cutting of coal or the like. Such power means may comprise a pair of shafts operatively connected to the non-rotatable body member, and rotatable with respect thereto, and interconnected to the cutting head through a cutting chain, and sprocket, arrangement. Both powered shafts are rotatable in the same direction, and effect coincident rotation of opposite sides of the cutting head.
Conveying means are mounted behind the cutting head in operative association with the body member for conveying material cut by the cutting head away from the cutting site in the dimension of elongation of the bore. The conveying means may comprise: a pair of auger flights operatively connected to the rotating shafts, and immediately posterior of the cutting head; scoop means disposed posteriorly of the auger flights and including a bottom portion substantially abutting the bore floor and extending posteriorly at a positive angle; and a conveyor belt disposed posteriorly of the scoop means and extending to the bore mouth, the scoop means funnelling toward the conveyor belt, and a top, transporting surface of the conveyor belt disposed adjacent the termination of the scoop means.
The machine also comprises means for pivoting the cutting head first axis about a generally horizontal second axis generally perpendicular to the bore dimension of elongation (and the dimension of elongation of the support side walls), so that the first axis is movable from a first cutting position of the cutting head substantially in-line with the conveying means, to other cutting positions vertically displaced from the first cutting position. A gamma ray sensor, or like sensing means, may be provided for automatically sensing the coal seam thickness. The sensor then controls the pivotal movement of the cutting head about the second axis to move either upwardly or downwardly to cut additional coal from the coal seam.
A conventional sumping means, such as shown in U.S. Pat. No. 4,120,535, is provided for moving the machine inwardly in the bore, and outwardly during periodic back-cutting thereof. The power means for powering all of the components, like the conveying means, extends to the bore mouth. Such an arrangement provides maximum safety, minimizes the complexity of construction of the in-bore components of the machine, and maximizes utility.
The invention also contemplates a method of mining coal from a generally horizontally extending coal seam. The cutting head is powered about the first axis, and the cutter is sumped inwardly into the coal seam a predetermined distance (e.g. 2 feet) to thereby cut coal from the coal seam to form a bore having a height approximately equal to the diameter of the cutting head (e.g. 26 inches). Then the cutting head is pivoted about a second horizontal axis, parallel to the first axis, so that the cutting head moves vertically in the bore and continues to cut coal from the coal seam while moving vertically. Then the cutting head is moved rearwardly toward the bore mouth while in its second position, to continue cutting from the coal seam to thereby enlarge the bore so that it has a height substantially equal to the diameter of the cutting head plus the vertical distance it has been moved. Cut coal is continuously conveyed to the bore mouth during all of the cutting steps, and the cutting steps are successively practiced while powering of the cutting head, and conveyance of the coal from the cutting site, are continued.
It is the primary object of the present invention to provide a mining machine, and method of mining, for the effective mining of coal or the like from generally horizontally extending seams. This and other objects of the invention will become clear from an inspection of the detailed description of the invention, and from the appended claims.